[ 04/61] regulator: clear state each invocation of of_regulator_match

From: Greg Kroah-Hartman
Date: Tue Feb 12 2013 - 16:11:18 EST

3.7-stable review patch. If anyone has any objections, please let me know.


From: Stephen Warren <swarren@xxxxxxxxxx>

commit a2f95c363701deba2205f81929b40222ea6f4f80 upstream.

of_regulator_match() saves some dynamcially allocated state into the
match table that's passed to it. By implementation and not contract, for
each match table entry, if non-NULL state is already present,
of_regulator_match() will not overwrite it. of_regulator_match() is
typically called each time a regulator is probe()d. This means it is
called with the same match table over and over again if a regulator
triggers deferred probe. This results in stale, kfree()d data being left
in the match table from probe to probe, which causes a variety of crashes
or use of invalid data.

Explicitly free all output state from of_regulator_match() before
generating new results in order to avoid this.

Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/regulator/of_regulator.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -120,6 +120,12 @@ int of_regulator_match(struct device *de
if (!dev || !node)
return -EINVAL;

+ for (i = 0; i < num_matches; i++) {
+ struct of_regulator_match *match = &matches[i];
+ match->init_data = NULL;
+ match->of_node = NULL;
+ }
for_each_child_of_node(node, child) {
name = of_get_property(child,
"regulator-compatible", NULL);

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